The present invention generally relates to optical communications networks and more particularly to configuring the carrier wavelength to be used by a first optical communication device to communicate with a second optical communication device.
Optical communications networks, and more particularly passive optical communications networks, are increasingly used to give network access to residential or office gateways or to ensure mobile backhauling for instance.
In an attempt to increase the number of users to be served by one access system to the network, wavelength or frequency division multiplexing technologies have been developed. These technologies take advantage of multiplexing several optical signals using different carrier wavelengths or frequencies on a single optical fiber. Even though some user terminals may share the same carrier wavelength or frequency, a wavelength or frequency splitter is typically used to separate the different wavelengths, or frequencies, in order to increase the number of simultaneous optical transmissions. The wavelength or frequency splitter is typically placed between the user terminals and a terminal providing access to the rest of the network. For instance this latter terminal provides access to a metropolitan network or a core network. Different techniques can be used to achieve the wavelength or frequency splitting. We can cite thin films based systems, interference cavities as AWG (Array Wavelength Gratings) and FBG (Fiber Bragg Gratings).
The wavelength or frequency splitter then comprises several optical band-pass filters, for each direction of communications. It is used to filter and combine optical signals issued by the user terminals toward the terminal giving access to the metropolitan or core network. In the other direction, it is used to filter and spectrally split the optical signals issued by the terminal giving access to the metropolitan or core network.